This invention relates to a semiconductor laser device having a low threshold current and also small in temperature dependency thereof.
It is well known that several structures of semiconductor lasers have been produced in which the threshold current is decreased. Among them a laser structure known as the so-called transverse junction stripe (abbreviated to "TJS") laser is particularly excellent. Such a TJS laser oscillates in the single mode and the characteristics thereof are described in detail, for example, in an H. Namizaki article entitled "Transverse-Junction-Stripe Lasers with a GaAs p-n Homojunction," IEEE Journal of Quantum Electronics, QE-11, Nov. 8, 1975, pages 427-431. However, the TJS laser has been disadvantageous in that a leakage current, not contributing to the laser oscillation, increases with a temperatures rise. This increase in leakage current causes a rapid increase in threshold current until the laser oscillation is ceased due to the heat generated therein.
Accordingly, it is an object of the present invention to provide a new and improved semiconductor laser device enabled to oscillate continuously even at temperatures which are somewhat higher than room temperature by minimizing the leakage current thereof.